Base rates of WAIS-R VIQ–PIQ differences in 1593 psychiatric inpatients

The purpose of this study was to provide the psychologist with base-rate tables for the Wechsler Adult Intelligence Scale—Revised (WAIS-R) Verbal IQ–Performance IQ difference scores in 1593 psychiatric inpatients. Subtables also were provided for each of three primary psychiatric diagnoses (schizophrenia spectrum disorders, bipolar disorders, and depression). The base rates of VIQ–PIQ splits in the full inpatient sample, and those for the subsamples based on primary psychiatric diagnosis, were very similar to those reported in the WAIS-R standardization sample. Consistent with past research on the standardization sample, the VIQ–PIQ split was correlated positively with Full Scale IQ (FSIQ), indicating that larger splits are more common at the higher IQ levels. Therefore, base-rate tables also were provided for the total inpatient sample split into five IQ groupings. © 2001 John Wiley & Sons, Inc. J Clin Psychol 57: 1579–1587, 2001.